Production of di-d-fructofranosyl-2,6′:2′,6-anhydride (DFA IV) by recombinant Bacillus subtilis carrying heterogenous levan fructotransferase from Arthrobacter nicotinovorans GS-9

We developed di-d-fructofranosyl-2,6′:2′,6-anhydride (DFA IV) production system with single culture of Bacillus subtilis directly from sucrose. This system can avoid the purification procedure of levan which organic solvent was used for precipitation. The levan fructotransferase (LFTase) gene was cloned from Arthrobacter nicotinovorans GS-9 (AHU1840, FERM P-15285) and expressed in levan producing B. subtilis 168. LFTase activity was detected in the culture supernatant of the transformant with maximal activity of 0.062 U/ml after 15.5 h post induction. Then sucrose was added as substrate and incubated. About 78 h after addition of sucrose, 20.5 g/l of DFA IV was produced from 139.3 g/l of sucrose consumed. The yield of DFA IV from sucrose was 14.7 wt.%.